History of the Catholic Church

According to the tradition of the Catholic Church, it started from the day of Pentecost at the upper room of Jerusalem ^[1]; the Catholic tradition considers that the Church is a continuation of the early Christian community established by the Disciples of Jesus. The Church considers its bishops to be the successors to Jesus's apostles and the Church's leader, the Bishop of Rome (also known as the Pope), to be the sole successor to St Peter^[2] who ministered in Rome in the first century AD after his appointment by Jesus as head of the Church.^[3][4] By the end of the 2nd century, bishops began congregating in regional synods to resolve doctrinal and administrative issues.^[5] Historian Eamon Duffy claims that by the 3rd century, the church at Rome might even function as a court of appeal on doctrinal issues.^[6]


Christianity spread throughout the early Roman Empire, with persecutions due to conflicts with the polytheist state religion. In 313, the persecutions were lessened by the Edict of Milan with the legalization of Christianity by the Emperor Constantine I. In 380, under Emperor Theodosius, Christianity became the state religion of the Roman Empire by the Edict of Thessalonica, a decree of the Emperor which would persist until the fall of the Western Roman Empire, and later, with the Byzantine (Eastern Roman) Empire, until the Fall of Constantinople. During this time, the period of the Seven Ecumenical Councils, there were considered five primary sees (jurisdictions within the Catholic Church) according to Eusebius: Rome, Constantinople, Antioch, Jerusalem, and Alexandria, known as the Pentarchy.


The battles of Toulouse preserved the Christian West against the Umayyad Caliphate of Sunni Islam, even though Rome itself was ravaged in 850, and Constantinople besieged. In the 11th century, already strained relations between the primarily Greek Church in the East, and the Latin Church in the West, developed into the East-West Schism, partially due to conflicts over papal supremacy. The Fourth Crusade, and the sacking of Constantinople by renegade crusaders proved the final breach. Prior to and during the 16th century, the Church engaged in a process of reform and renewal. Reform during the 16th century is known as the Counter-Reformation.^[7] In subsequent centuries, Catholicism spread widely across the world despite experiencing a reduction in its hold on European populations due to the growth of Protestantism and also because of religious skepticism during and after the Enlightenment. The Second Vatican Council in the 1960s introduced the most significant changes to Catholic practices since the Council of Trent four centuries before.